All eyes have been on Avengers: Infinity War as its end-of-the-month release date approaches. But after The Russo Brothers shot Infinity War, they started filming the untitled Avengers 4 movie.

With that, Games Radar asked the directing duo which one was harder to shoot.

"Good question,” said Joe Russo. "I think [Infinity War] only because it was a compressed time frame and we were posting it while we were shooting Avengers 4. We were really doing double duty while we were making that movie."

But movie-goers won't see the fruits of their labor for Avengers 4 until next year.

In the meantime, they're gearing up to screen Infinity War—although it won't be shown "in its entirety" until the Los Angeles premiere. "Everyone involved with the film has worked incredibly hard for the past two years maintaining the highest level of secrecy," said the brothers in a statement on Twitter who also shared that "only a handful of people know the film's true plot."

The brothers also asked for movie-goers to restrain from sharing spoilers. "We’re asking that when you see Infinity War, in the coming months, that you maintain that same level of secrecy so that all fans can have an equal experience when they watch it for the first time. Don’t spoil it for others, the same way you wouldn’t want it spoiled for you."

With character deaths looming and promises of the Marvel Cinematic Universe heading into a "massively different" territory after the next few films, its likely to be worth it.

Infinity War is slated to hit theaters on April 27, while the untitled Avengers 4 film is scheduled to land in theaters in 2019.